In this study, we aim to evaluate the effect of cerium oxide nanoparticles on cell antioxidant (SOD, TAC (total antioxidant capacity), thiol, and CAT (catalase)), toxicity, as well as cell oxidant (ROS and MDA (malondialdehyde)) levels in esophageal cancer (YM1) and cancer stem cell-like (CSC-LC) cell lines. The gene discussed is SOD1; the disease is cancer.